From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Joe Lawrence <joe.lawrence@redhat.com>,
Jessica Yu <jeyu@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
x86@kernel.org, linux-kernel@vger.kernel.org,
mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com,
torvalds@linux-foundation.org, tglx@linutronix.de,
mingo@kernel.org, namit@vmware.com, hpa@zytor.com,
luto@kernel.org, ard.biesheuvel@linaro.org,
live-patching@vger.kernel.org
Subject: Re: [PATCH v3 5/6] x86/ftrace: Use text_poke()
Date: Mon, 21 Oct 2019 10:05:49 -0500 [thread overview]
Message-ID: <20191021150549.bitgqifqk2tbd3aj@treble> (raw)
In-Reply-To: <20191016074217.GL2328@hirez.programming.kicks-ass.net>
On Wed, Oct 16, 2019 at 09:42:17AM +0200, Peter Zijlstra wrote:
> > which are not compatible with livepatching. GCC upstream now has
> > -flive-patching option, which disables all those interfering optimizations.
>
> Which, IIRC, has a significant performance impact and should thus really
> not be used...
>
> If distros ship that crap, I'm going to laugh at them the next time they
> want a single digit performance improvement because *important*.
I have a crazy plan to try to use objtool to detect function changes at
a binary level, which would hopefully allow us to drop this flag.
But regardless, I wonder if we enabled this flag prematurely. We still
don't have a reasonable way to use it for creating source-based live
patches upstream, and it should really be optional for CONFIG_LIVEPATCH,
since kpatch-build doesn't need it.
--
Josh
next prev parent reply other threads:[~2019-10-21 15:06 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 9:02 [RESEND] everything text-poke: ftrace, modules, static_call and jump_label Peter Zijlstra
2019-10-07 8:17 ` [PATCH v3 0/6] Rewrite x86/ftrace to use text_poke() Peter Zijlstra
2019-10-07 8:17 ` [PATCH v3 1/6] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-10-08 14:29 ` Borislav Petkov
2019-10-08 14:40 ` Steven Rostedt
2019-10-08 14:50 ` Borislav Petkov
2019-10-08 14:48 ` Peter Zijlstra
2019-10-08 14:54 ` Borislav Petkov
2019-10-08 15:04 ` Steven Rostedt
2019-10-08 15:24 ` Borislav Petkov
2019-10-09 12:03 ` Daniel Bristot de Oliveira
2019-10-07 8:17 ` [PATCH v3 2/6] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra
2019-10-07 8:17 ` [PATCH v3 3/6] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra
2019-10-09 12:04 ` Daniel Bristot de Oliveira
2019-10-07 8:17 ` [PATCH v3 4/6] x86/alternatives: Add and use text_gen_insn() helper Peter Zijlstra
2019-10-08 6:23 ` Masami Hiramatsu
2019-10-08 8:15 ` Peter Zijlstra
2019-10-07 8:17 ` [PATCH v3 5/6] x86/ftrace: Use text_poke() Peter Zijlstra
2019-10-08 14:43 ` Steven Rostedt
2019-10-08 17:11 ` Peter Zijlstra
2019-10-08 17:27 ` Steven Rostedt
2019-10-10 2:41 ` Steven Rostedt
2019-10-10 9:20 ` Peter Zijlstra
2019-10-10 13:19 ` Steven Rostedt
2019-10-10 14:05 ` Peter Zijlstra
2019-10-10 15:54 ` Steven Rostedt
2019-10-10 17:28 ` Peter Zijlstra
2019-10-10 17:48 ` Steven Rostedt
2019-10-11 10:45 ` Peter Zijlstra
2019-10-11 10:47 ` Peter Zijlstra
2019-10-11 10:50 ` Peter Zijlstra
2019-10-11 12:59 ` Peter Zijlstra
2019-10-11 13:33 ` Steven Rostedt
2019-10-11 13:45 ` Peter Zijlstra
2019-10-15 13:07 ` Jessica Yu
2019-10-15 13:56 ` Peter Zijlstra
2019-10-15 14:11 ` Peter Zijlstra
2019-10-15 14:13 ` Miroslav Benes
2019-10-15 15:06 ` Joe Lawrence
2019-10-15 15:31 ` Jessica Yu
2019-10-15 22:17 ` Joe Lawrence
2019-10-15 22:27 ` Steven Rostedt
2019-10-16 7:42 ` Peter Zijlstra
2019-10-16 10:15 ` Miroslav Benes
2019-10-21 15:05 ` Josh Poimboeuf [this message]
2020-01-20 16:50 ` Josh Poimboeuf
2020-01-21 8:35 ` Miroslav Benes
2020-01-21 16:10 ` Josh Poimboeuf
2020-01-22 10:09 ` Miroslav Benes
2020-01-22 21:42 ` Josh Poimboeuf
2020-01-28 9:28 ` Miroslav Benes
2020-01-28 15:00 ` Josh Poimboeuf
2020-01-28 15:40 ` Petr Mladek
2020-01-28 17:02 ` Josh Poimboeuf
2020-01-29 0:46 ` Jiri Kosina
2020-01-29 2:17 ` Josh Poimboeuf
2020-01-29 3:14 ` Jiri Kosina
2020-01-29 12:28 ` Miroslav Benes
2020-01-29 15:59 ` Josh Poimboeuf
2020-01-30 9:53 ` Petr Mladek
2020-01-30 14:17 ` Josh Poimboeuf
2020-01-31 7:17 ` Petr Mladek
2020-01-22 12:15 ` Miroslav Benes
2020-01-22 15:05 ` Miroslav Benes
2020-01-22 22:03 ` Josh Poimboeuf
2020-01-23 10:19 ` Martin Jambor
2019-10-16 7:49 ` Peter Zijlstra
2019-10-16 10:20 ` Miroslav Benes
2019-10-16 13:29 ` Miroslav Benes
2019-10-18 13:03 ` Jessica Yu
2019-10-18 13:40 ` Petr Mladek
2019-10-21 14:14 ` Jessica Yu
2019-10-21 15:31 ` Josh Poimboeuf
2019-10-22 8:27 ` Miroslav Benes
2019-10-22 14:31 ` Josh Poimboeuf
2019-10-23 9:04 ` Miroslav Benes
2019-10-16 6:51 ` Miroslav Benes
2019-10-16 9:23 ` Peter Zijlstra
2019-10-16 9:36 ` Jessica Yu
2019-10-16 9:51 ` Peter Zijlstra
2019-10-16 12:39 ` Peter Zijlstra
2019-10-22 8:45 ` Miroslav Benes
2019-10-15 14:42 ` Peter Zijlstra
2019-10-15 18:31 ` Peter Zijlstra
2019-10-15 15:51 ` Jessica Yu
2019-10-15 13:28 ` Steven Rostedt
2019-10-15 13:42 ` Peter Zijlstra
2019-10-15 16:09 ` Jessica Yu
2019-10-07 8:17 ` [PATCH v3 6/6] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra
2019-10-08 15:07 ` [PATCH v3 0/6] Rewrite x86/ftrace to use text_poke() Steven Rostedt
2019-10-07 8:25 ` [PATCH v2 0/4] Propagate module notifier errors Peter Zijlstra
2019-10-07 8:25 ` [PATCH v2 1/4] notifier: Fix broken error handling pattern Peter Zijlstra
2019-10-10 22:01 ` Rafael J. Wysocki
2019-10-07 8:25 ` [PATCH v2 2/4] module: Fix up module_notifier return values Peter Zijlstra
2019-10-23 19:25 ` Steven Rostedt
2019-10-07 8:25 ` [PATCH v2 3/4] module: Properly propagate MODULE_STATE_COMING failure Peter Zijlstra
2019-10-08 13:08 ` Miroslav Benes
2019-10-07 8:25 ` [PATCH v2 4/4] jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved Peter Zijlstra
2019-10-23 19:29 ` Steven Rostedt
2019-10-07 8:27 ` [PATCH v2 00/13] Add static_call() Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 01/13] compiler.h: Make __ADDRESSABLE() symbol truly unique Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 02/13] static_call: Add basic static call infrastructure Peter Zijlstra
2019-10-07 11:33 ` Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 03/13] static_call: Add inline " Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 04/13] static_call: Avoid kprobes on inline static_call()s Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 05/13] x86/static_call: Add out-of-line static call implementation Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 06/13] x86/static_call: Add inline static call implementation for x86-64 Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 07/13] static_call: Simple self-test Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 08/13] tracepoints: Use static_call Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 09/13] x86/alternatives: Teach text_poke_bp() to emulate RET Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 10/13] static_call: Add static_cond_call() Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 11/13] static_call: Handle tail-calls Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 12/13] static_call: Allow early init Peter Zijlstra
2019-10-07 8:27 ` [RFC][PATCH v2 13/13] x86/perf, static_call: Optimize x86_pmu methods Peter Zijlstra
2019-10-07 11:33 ` [PATCH v2 00/13] Add static_call() Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 0/9] Variable size jump_label support Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 1/9] jump_label, x86: Strip ASM " Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 2/9] jump_label, x86: Factor out the __jump_table generation Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 3/9] jump_label, x86: Remove init NOP optimization Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 4/9] jump_label, x86: Improve error when we fail expected text Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 5/9] jump_label, x86: Introduce jump_entry_size() Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 6/9] jump_label, x86: Add variable length patching support Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 7/9] jump_label,objtool: Validate variable size jump labels Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 8/9] jump_label,objtool: Generate possible statistics Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 9/9] jump_label, x86: Enable JMP8/NOP2 support Peter Zijlstra
2019-10-07 12:07 ` [RFC][PATCH 0/9] Variable size jump_label support Peter Zijlstra
2019-10-07 12:55 ` Ingo Molnar
2019-10-07 15:08 ` Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191021150549.bitgqifqk2tbd3aj@treble \
--to=jpoimboe@redhat.com \
--cc=ard.biesheuvel@linaro.org \
--cc=bristot@redhat.com \
--cc=hpa@zytor.com \
--cc=jbaron@akamai.com \
--cc=jeyu@kernel.org \
--cc=joe.lawrence@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=live-patching@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mbenes@suse.cz \
--cc=mhiramat@kernel.org \
--cc=mingo@kernel.org \
--cc=namit@vmware.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).